Log-Exponential Mapping for High-Dynamic Range Video on Low Resolution Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High-performance imaging sensors with dynamic ranges greater than 8 bits/pixel face challenges when displaying high-dynamic range data on lower dynamic range displays, as existing mapping methods like linear and gamma functions result in loss of image dynamic range or saturation.
Innovation Solution
A pilot-selectable Log-Exponential (Log-Exp) mapping function is introduced, allowing for multiple selectable modes that provide a wide range of displayed dynamic ranges by using the sensor output value in the exponent, rather than the base, to effectively map high-dynamic range data to lower-dynamic range displays without clipping or saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear mapping is used to map high-dynamic range sensor data to low-dynamic range display, then the mapping is simple, but the image dynamic range is lost across the entire display
Solution Approach 1:
The patent applies parameter changes by transforming the mapping function from linear to exponential form. Specifically, it uses functions like Y = A * exp(BX) where the sensor output X is in the exponent, allowing the mapping to preserve dynamic range characteristics across different brightness levels while adapting to the display's limited range
Solution Approach 2:
The patent implements dynamic mapping by providing multiple selectable exponential mapping modes (different A and B parameters) that can be chosen based on the specific imaging scenario. This allows the system to dynamically adapt the mapping characteristics to preserve relevant dynamic range information for different operational conditions
2Loss of information
If gamma function mapping is used to map high-dynamic range sensor data to low-dynamic range display, then the mapping is non-linear, but it is prone to saturation where dynamic range is entirely lost
Solution Approach 1:
The patent changes the functional form from gamma (power law) to exponential mapping. This fundamental parameter change in the mapping function prevents the saturation behavior inherent in gamma functions while maintaining the ability to non-linearly distribute dynamic range information across the display capability
Solution Approach 2:
The patent creates multiple exponential mapping function variants (different A and B parameters) that can be selected based on the imaging conditions. This provides alternative mappings that avoid saturation in different brightness scenarios, effectively copying the essential dynamic range preservation capability across multiple functional forms
3Ease of operation
If brightness adjustable display is used to allow adjustability of brightness, then the display is simple to operate, but the mapping scheme is not altered other than gain increase or decrease
Solution Approach 1:
The patent extends simple brightness adjustment to dynamic mapping mode selection. Users can select from multiple exponential mapping modes with different characteristics (parameters A and B), allowing the system to dynamically adapt the mapping strategy to preserve dynamic range in different brightness scenarios rather than simply applying gain changes
Solution Approach 2:
The patent makes the display system multi-functional by combining brightness adjustment with selectable mapping modes. Each mode serves different operational requirements, making the system universally applicable to various imaging scenarios while maintaining ease of operation through pilot-selectable modes
Data Source
AI summary
A method and system for displaying to a pilot, or other airborne personnel, high resolution video signal content on a lower resolution display, by providing a plurality of pilot selectable aspects of the high resolution video signals, which are predetermined to accentuate a particular characteristic of said high resolution video signals, where the aspects are non-linear mappings of the high resolution signals (x) to (y) on said lower resolution display, where the non-linear mapping has y determined by a constant with an exponent which includes x and a logarithmic constant.